Extracellular polymeric substances from Shewanella oneidensis MR-1 biofilms mediate the transformation of Ferrihydrite
Extracellular polymeric substances from Shewanella oneidensis MR-1 biofilms mediate the transformation of Ferrihydrite
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来自 Shewanella oneidensis MR-1 生物膜的细胞外聚合物介导水铁矿的转化
DOI：
10.1016/j.scitotenv.2021.147245
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发表时间：
2021
影响因子：
9.8
通讯作者：
Jing Chuanyong
中科院分区：
文献类型：
--
作者：
Yan Wei;Guo Wen;Wang Liying;Jing Chuanyong
异化铁还原菌（DIRB）如Shewanella oneidensis MR-1的胞外聚合物（EPS）在含铁矿物的生物转化过程中起着重要作用，但其作用机制尚未完全阐明。本文比较了水铁矿（Fh）的非生物转化和生物转化，以阐明MR-1、无EPS的MR-1（MR-1-EPS）、松散结合的EPS（LB-EPS）和紧密结合的EPS（TB-EPS）的贡献。非生物Fh转化的结果表明，EPS没有阻止Fh表面，因此对吸附的Fe（II）-Fh相互作用的影响不显著。Fe（III）中间体（活性Fe（III））与EPS，尤其是LB-EPS的络合作用，抑制了次生Fe矿物的成核，改变了结晶途径。另一方面，对于生物Fh转化，EPS具有双重作用，即由于增强的细胞外电子转移（EET）而加速Fh生物还原，并通过切断导致矿物结晶的链式反应来限制随后的Fh矿化。我们的研究结果还表明，EPS对Fh生物转化的影响在很大程度上取决于EPS的化学性质，特别是羧基和磷酸根等极性官能团，因为它们对细胞附着和Fe（II）/Fe（III）具有重要的作用。结合。
Extracellular polymeric substances (EPS) of dissimilatory iron-reducing bacteria (DIRB) such asShewanella oneidensisMR-1 play a crucial role in the biotransformation of iron-containing minerals, but the mechanism has not been fully deciphered. Herein, abiotic and biotic transformation of ferrihydrite (Fh) were compared to clarify the contributions of MR-1, EPS-free MR-1 (MR-1-EPS), loosely bound EPS (LB-EPS), and tightly bound EPS (TB-EPS). The results of abiotic Fh transformation indicated that EPS did not block the Fh surfaces and thus has an insignificant effect on the adsorbed Fe(II)-Fh interaction. The complexation of the Fe(III) intermediate (Fe(III)active) with EPS, especially LB-EPS, however, inhibited the nucleation of secondary Fe minerals and changed the crystallization pathway. For biotic Fh transformation, on the other hand, EPS had dual effects that accelerated Fh bioreduction due to the enhanced extracellular electron transfer (EET) and constrained the following Fh mineralization by cutting of the chain reactions leading to mineral crystallization. Our finding also suggested that the effects of EPS on Fh biotransformation largely depend on the chemical properties of EPS, especially the polar functional groups such as carboxyl and phosphate, because of their important abilities for the cell attachment and Fe(II)/Fe(III) binding.